Monday, October 15, 2001		Article

ALL electronic computers make use of binary code — 1’s and 0’s, or on’s and off’s on the circuits of a computer chip, forming the basis for every calculation a computer performs, from simple addition to the solution of the most complex differential equations. A conventional computer represents information on silicon chips as a series of electrical impulses — zeroes and ones — and manipulates the information by performing mathematical computations with those zeroes and ones.

Though these machines can do miracles in completing different mathematical operations yet they work according the instructions given to them by the human. Moreover, transistors and electrical circuits written on silicon chip (i.e., brain of electronic computers) have been greatly reduced in size. This miniaturisation has driven enormous growth in the speed and power of computer processing.

But chip designers think they will hit a size barrier in the times to come. Besides, the electronic computers do not possess their own brain as compared to the human beings. Scientists and technologists have always strived for the development of computers with brainpower. Recently, scientists found an answer in terms of Deoxyribo Nucleic Acid (DNA) molecules — the building blocks of life — and are working for the development of practical machines (i.e., say DNA or Molecular computers) with brainpower. Researchers are turning to DNA’s chief attributes — its microscopic size and powerful search function that can explore all possible answers simultaneously — to build "computers with brain".

The DNA represents information as a pattern of molecules on a strand of the DNA. Each strand represent one possible answer and trillions of strands of the DNA can be embedded on a gold-coated square of glass about 1 inch square that is believed to be the optimum working surface.

The DNA molecule is also a code, made up of a sequence of four bases that pair up in a predictable manner making possible for using it as a molecular computer. Thus, DNA — the twisted strands of life that govern heredity — instead of silicon is one key to building a radically different kind of computer to store and manipulate information. At present the technology for the DNA computing and biocomputing is so rudimentary that demonstrations have been limited to questions that a human could answer without any computer at all.

Eventually, proponents say, the technology could produce DNA-based computers that would be better even than today’s supercomputers in solving certain types of problems.

DNA computing experiments have been heralded as the "examples of true nanotechnology", and even the "start of a new era," forging an unprecedented link between computational science and life science. In speed, the DNA clearly wins the race, performing 1,000 operations per second more than the fastest supercomputers (which execute about 1012 operations per second). To get a better idea of the speed, consider that a typical desktop computer performs a thousand million times slower than the DNA, a measly 106 operations per second.

The potential for information storage in molecular computers follows the same trend as speed and efficiency. While storage media of today, such as videotapes, store information at a density of one bit per 1012 cubic nanometers, the molecules of DNA make this figure seem ridiculous, with an information storage density of 1 bit per cubic nanometer - a trillion times less space.

Even though, molecular computer would have a hard time multiplying two 100-digit integers, an easy task for one of today’s electronic computers, its capability to solve complex problems is unparalleled. DNA computers will specialise in large computational problems in which the number of possible answers is enormous.

However, as work continues in this exciting area, molecular computers may impress us once again and challenge the dominance of electronic systems in solving even more types of problems. After all, the DNA based system of computation has had millions of years to evolve and perfect itself, while man-made systems have only existed for a small fraction of this span.